著者

久保田 信 田名瀬 英朋

出版者

日本生物地理学会

雑誌

日本生物地理学会会報 (ISSN:00678716)

巻号頁・発行日

vol.61, pp.75-79, 2006-12-30

---

Fresh-water hydromedusae, Craspedacusta sowerbyi Lankester (Hydrozoa, Limnomedusae, Ohndiidae), were found in three ponds and a dam reservoir in Tanabe city and Shirahama town, Wakayama Prefecture, between the years 1996 and 2006. The morphology of mature female and male medusae, nematocysts in the tentacles, and sperm is described. The biggest medusa was 22 mm in diameter with a large number oftentacles, up to 514 in several circlets. The present specimens are larger and more complicated in morphology than those of the same species described from China and Korea, while specimens with many more tentacles (up to ca 700) have been reported from other prefectures in Japan. The present specimens did not display parthenogenesis.